U.S. Pat. Nos. 4,116,856; 4,116,858; and 4,159,311 disclose the in-situ formation of hydrous alumina, by ammonia precipitation of Al halide, within anion exchange resins, followed by reaction of the hydrous alumina with Li halide to form crystalline LiX.2Al(OH).sub.3, where X is halide. Such resin/aluminate composites are disclosed as being useful in recovering Li.sup.+ values from Li.sup.+ -containing aqueous solutions.
It is also known that the amount of such hydrous alumina that can be thus precipitated in a weak-base anion exchange resin can be increased by subsequent additional application of Al halide, followed by the ammonia precipitation, so long as the weak-base resin is converted back to its halide salt form under mildly acid conditions (e.g., pH 5-6.5) before such additional application of Al halide. Maximum loading of hydrous alumina is approached by repeated precipitation steps.